Abstract:Objective:To investigate the changes of TLR4 expression in ileum of the rat after ischemia/reperfusion (I/ R) injury, and the relationship between TLR4 gene expression and TNF-α、IL-6 level in blood of portal vein.
Methods :A totol of 90 adult male SD rats were randomized into 3 groups: normal control group(n=10), sham-operated group(n=40) and ileum ischemia / reperfusion group(n=40).Animals were sacrificed after undergoing ileum ischemia/reperfusion injury for 6、12、24 and 48 h，and expression of TLR4 mRNA was determined by RT-PCR. Meanwhile, blood in portal vein was obtained to assay TNF-α and IL-6 concentration in plasma.Correlation analysis between TLR4 mRNA and TNF-α、IL-6 levels was made. Expression of TLR4 in ileum was evaluated with immunohistochemistry.
Results:The expression of TLR4mRNA in ileum and TNF-α and IL-6 level in portal vein plasma was significantly higher in experimental group, compared with sham group (P<0.05). TLR4mRNA expression peaked at 12 h after I/ R injury, and TNF-αand IL-6 concentration peaked at 24h. TLR4mRNA expression and TNF-αand IL-6 level showed significant relativity(r=0.812 and 0.752). Immunohistochemical exam showed TLR4 was mainly expressed in ileum mucous membrane.
Conclusions:Expression of TLR4 in ileum was up-regulated after I/ R injury in rat, and that could be one of the mechanisms of intestinal mucosal barrier function injury, as well as the trigger for initiation of systemic inflamatory response syndrome(SIRS).